Taï Forest ebolavirus is a distinct species of the genus Ebolavirus, formerly known as Côte d’Ivoire ebolavirus. It was identified in 1994 after an outbreak among western chimpanzees in Taï National Park, Côte d’Ivoire, and infection of a scientist performing a necropsy. The virus is a negative‑sense single‑stranded RNA virus of the family Filoviridae, enveloped and filamentous, causing Ebola virus disease in non‑human primates and, in rare instances, humans.
Features and Discovery
Taï Forest ebolavirus has a genome of about 19 kilobases encoding seven structural proteins: nucleoprotein (NP), VP35, VP40, glycoprotein (GP), VP30, VP24 and the RNA‑dependent RNA polymerase (L). Virions are pleomorphic filaments containing a helical nucleocapsid and a host‑derived lipid envelope. Genetic analysis shows that Taï Forest ebolavirus is most closely related to Zaire ebolavirus yet distinct enough to warrant a separate species name. The virus was discovered in 1994 when a sudden die‑off of western chimpanzees occurred in Taï National Park. A Swiss scientist who performed an autopsy on one of the chimpanzees developed symptoms of Ebola virus disease but survived; isolation and sequencing of the virus from her blood revealed a new ebolavirus species. Subsequent surveys have detected antibodies to ebolaviruses in fruit bats in the region, suggesting a reservoir, though Taï Forest ebolavirus has not been isolated from bats. The virus replicates in monocytes, macrophages and dendritic cells, triggering release of pro‑inflammatory cytokines and causing vascular leakage. Because only one human case has been documented, the case fatality rate in humans is unknown; all documented primate outbreaks resulted in high mortality among affected animals. No licensed vaccines or therapeutics specifically target Taï Forest ebolavirus, and cross‑protection from existing ebolavirus vaccines is untested.
Notable Outbreaks and Insights
The 1994 Taï National Park outbreak remains the only known event involving Taï Forest ebolavirus. It affected a community of wild chimpanzees, causing haemorrhagic disease and many deaths. The single human case recovered after supportive care, which included transfer to Switzerland and administration of broad‑spectrum antivirals and interferon. In 2004 another die‑off of chimpanzees in Taï National Park was associated with an ebolavirus, although no viral isolates were obtained; serology suggested exposure to Taï Forest or a related virus. These events highlight the risk of zoonotic transmission from non‑human primates to humans, particularly during necropsy or direct contact with tissues. The rarity of human cases may reflect limited human–wildlife contact or lower transmissibility compared with other ebolaviruses. Continued monitoring of wildlife mortality events and serologic surveys in bats and primates are critical to understanding the ecology of Taï Forest ebolavirus and preventing spillover.
Taï Forest ebolavirus illustrates the diversity within the Ebolavirus genus and underscores the importance of surveillance in wildlife populations. Although human cases are exceedingly rare, ongoing research and preparedness are essential to detect and respond to potential future spillovers.
Related Terms: Zaire Ebolavirus, Sudan Ebolavirus, Bundibugyo Ebolavirus, Reston Ebolavirus, Bombali Ebolavirus